A self-propelled apparatus is a robotic mobile intelligent device that is able to make decisions or take a detour to avoid obstacles according to the conditions of roads automatically and independently. For instance, it can be adapted for powered wheelchairs for enabling the same to recognize an uphill and accelerate accordingly, or to recognize a downhill and decelerate automatically. In addition, as it is designed to make an evaluation to determine whether to take a detour or stride over when it runs into an obstacle, it is suitable for applications, such as robots, autonomous mobile platforms, or robotic vacuum cleaners, etc. An intelligent vacuum cleaner can substantially improve the quality and convenience of our lives since it can maneuver around obstacles, e.g. furniture, in our household while cleaning floors, moreover, it can clean those dead spots that are not accessible using conventional cleaning tools as it can enter areas beneath larger furniture, such as beds, sofas, and so on.
From the above description, it is noted that the focal point of designing a good robotic mobile intelligent device is the ability to detect the conditions of roads automatically and independently. Usually, conventional robotic mobile apparatuses detect obstacle by emitting ultrasonic waves or infrared light. However, such ultrasonic or infrared sensors can only detect and sense obstacles blocking its moving path and plan a detour accordingly, they are not capable of detecting road conditions on its moving path and thus adjusting its moving speed accordingly.
Another detection method commonly being adopted by those conventional robotic mobile apparatuses is exercised by arranging an encoder on a DC motor for measuring that the rotation speed of the DC motor according to the pulse train of the encoder, and further controlling the output of the DC motor basing upon the road conditions analyzed with respect to the rotation speed. The two aforesaid detections all require the use of certain sensors for detecting and measuring certain external signals originating from ambient environment.
Therefore, it is intended in this invention to provide a method capable of detecting and measuring input impedance related to a DC motor while basing upon the detection/measurement to analyze the DC motor's output characteristics, that it can detect actual operating status of the DC motor without relying upon the detection of those torque sensors or rotation sensors currently available on the market, and thereby, not only the manufacturing cost of the DC motor can be reduced, but also the complication of designing a closed-circuit controller is minimized.